Constant surveillance alarm system



'June'l'7, 1969 P. A. SCHUMANN CONSTANT SURVEILLANCE ALARM SYSTEM Filed June 16, 1965 Human IMZOQ u u K INVENTOR Paul A. Schumann BY y z 87. m

Tm QQ wit QThuk 9 6 bu $3M QIVE Fm IVE mm Tm ATTORNEY United States Patent US. Cl. 340-412 23 Claims ABSTRACT OF THE DISCLOSURE A constant surveillance alarm system including a central monitoring station connected with a plurality of remote field points through a limited number of conductors wherein each field point includes alarm contact means and relay contact means and the field points are arranged to form a plurality of groups, each group having a relay for operating the relay contacts of the field points associated therewith whereby the field point at which an alarm condition exists may be determined by energizing the relay associated with the group containing the field point sensing the alarm condition which group may be determined by visual means.

This invention relates generally to a constant surveillance alarm system, and more particularly to an alarm system including a plurality of multiplex relays through which a plurality of remotely-located field or alarm contact means are connected with a central monitoring station by means of a limited number of intermediate conductors. The invention is characterized by the provision, at the central station, of alarm means responsive to the closure of any one of the field contacts, and separate indicator means for identifying said one field contact by means of the specific relay, and the specific branch circuit of that relay, with which it is associated.

In the known systems for monitoring a plurality of remotely located conditions (as might be found in the different zones of a multi-storied building, for example), condition-responsive sensing means are generally placed at various remote locations and signals therefrom are transmitted to a centrally-arranged control station. In many of the known systems, it is conventional to provide at the central station a separate indicating light for each of the field contacts and to connect these two components by separate wires. Electrical circuits of this type are expensive and complex, owing to the large number of conductors, signal lamps, and components therefore required by the system.

It is, therefore, an object of the present invention to avoid the above and other drawbacks of the known systems by an alarm system of the multiplex relay type employing a minimum number of indicating lights and a minimum number of conductors for connecting these lights with the field contacts.

Another object of the present invention is to improve a constant surveillance alarm system by means of a plurality of normally-open field alarm contacts connected in series with the contacts of a plurality of identical multiplex relays, respectively, and a relatively small number of successively operated first and second indicator light 3,451,058 Patented June 17, 1969 means for indicating initially the specific relay, and subsequently the specific branch circuit of that relay, with which a given closed field contact is associated. As a result of the invention, the number of first and second signal lights required by the system is greatly reduced and need equal only the sum of the number of relays and the number of contacts of any relay. Furthermore, the number of conductors required for connection to the central location is reduced and is approximately equal to the sum of the number of contacts of a relay and twice the number of relays provided in the system.

This invention has another object in that a multiplex alarm system of the type described above includes audible alarm means activated upon the actuation of any one of a plurality of remotely-arranged field contact means, in combination with first and second visible indicator means for indicating the specific relay and the specific relay branch associated with such actuated field contact means. A further object of the invention is to provide an alarm system of the type described above with test circuit means for selectively energizing all of the visible indicating means to ascertain the operability thereof.

In accordance with the present invention, alarm acknowledgement means are provided for manually deactivating the audible alarm following recognition of the alarm condition. Following indication by the first visible indicator means of the specific relay with which the field contact is associated, switch means are operated to close all of the relay contacts of this relay and thereby energize that one of the circuit branch indicators which is associated with the closed field contact. Means responsive to the energization of any of the second indicator means serve to reset the audible alarm means to a condition responsive to closure of any other field contact.

Others objects and advantages of the invention will become apparent from a study of the following description when considered in conjunction with the accompanying drawing in which:

FIG. 1 is a schematic electrical diagram of the alarm system embodying the present invention; and

FIG. 2 is a partial schematic electrical diagram of a modification of FIG. 1.

As is illustrated in FIG. 1 of the drawing, a plurality of field alarm contacts FC11 through FC610 are connected in series with the relay contacts RC1-1 through RC610, respectively, of ten point multiplex relays R1 through R6. The free ends of the field contacts are connected with the positive terminal of a 24-volt direct-current voltage source 10 by means of a common conductor 12. The corresponding series branches (including a field alarm contact connected in series with a relay contact) of each relay are connected in parallel by ten first conductor means 14, respectively. The ten parallel branches thus formed are connected'in series with ten pilot signal lights L01 through LC10 by ten second conductor means 16, respectively. At their other ends, the conductor means 16 have a common junction 18 connected via conductor 20 and junction 22 to a ground terminal 24; of course, the ground terminal 24 may be connected to the negative terminal of source 10.

Associated with the relay contacts are a plurality of equally-poled isolating diodes DR1-1 through DR6-10 having common electrodes connected with the series branches between the field alarm and relay contacts thereof, respectively. The other electrodes of the six groups of diodes associated with relays R1 through R6 are connected by third conductor means 26 to six relay output terminals T1 through T6, respectively. These output terminals are connected by six fourth conductor means 28 with one side of six pilot lights LR1 through LR6, respectively, the other sides of which are connected with common junction 22.

Each of the relays R1 through R6 includes an operating coil RM1 through RM6 energizable to close the associated ten relay contacts, respectively. These coils are connected at one end with the positive conductor 12 and at their other ends with the negative terminal of source via six conductors 30 that contain series-connected normally-open switches S1 through S6, respectively.

In accordance with the invention, a normally de-energized audible alarm 40 is provided having a relay coil RM7 one side of which is connected with each of the fourth conductor means 28 by six fifth conductor means 42, respectively, the other end of the coil being connected with junction 22 via conductor 45. Conductors 42 contain normally closed relay contacts 44 that are opened by energization of the corresponding relay coils K1 through K6, respectively. Equally-poled isolating diodes 46 are also connected in each of the conductor means 42, respectively.

One side of each of the relay coils K1 through K6 is connected with the common conductor 20. The other sides of the relay coils are connected with the corresponding conductors 28 by six conductor means 50 containing normally-open switches K01 through KC6, respectively, that are operated by the relay coil K8 which is connected in series with alarm acknowledgement switch SAA across the positive and negative leads 12 and 30, respectively. Each of the relay-operated switches 44 is provided with holding circuit means including auxiliary stationary contacts 54 operable to connect the relay coils K1 through K6 between conductor and the corresponding fi-fth conductors 42, respectively.

In accordance with another feature of the invention, test circuit means are provided for energizing the lights to determine the operability thereof. To this end, conductors 16 and 28 are connected with the positive terminal of the DC voltage source 10 via diodes 60 and common conductor 62. Consequently, closure of test switch ST effects energization and illumination of all of the operable lamps.

In describing the operation of the system of FIG. 1, it is assumed that initially all of the field alarm contacts are open, that all of the switches are in their illustrated condition, and that all of the signal lights are de-energized.

Assume now that for some reason (such as a sensed condition in a remotely located zone exceeding a predetermined value), the field alarm contact FC1-1 is closed. A current path is now established from the positive pole of voltage source 10 via conductor 12, field contact FCl-l, diode DRl-l, terminal T1, conductor 28a and pilot light LR-l to ground terminal 24. Current also flows from conductor 28a to junction 22 via conductor 42a, switch 44a, diode 46a and relay coil RM7, thereby energizing the audible alarm 40. Owing to the illumination of lamp LR1, the operator is advised that at least one of the field contacts connected with relay R1 is closed.

The operator now closes alarm acknowledge switch SAA, whereby the relay K8 is energized to close the six switch contacts KC-l through KC-6. Current now flows from conductor 28a through conductor 50a, contacts KC-l, relay coil K1, conductor 20 and junction 22 to the ground terminal 24. Since no current flows through the remaining coils K2 through K6 at this time, these relays remain de-energized. Owing to the energization of relay K1, contact 44a is displaced into engagement with stationary contact 54a, whereby audible alarm 40 is deenergized and whereby a relay holding circuit is established by the flow of current from conductor 28a through conductor 42a, contact 44a, contact 54a, coil K1, conductor 20 and junction 22 to the ground terminal 24. Consequently, upon release of alarm acknowledgement switch SAA, relay K1 is maintained energized by its holding circuit.

Knowing now from the energization of pilot light LR1 the relay with which the closed field contact is related, the operator closes switch S1, whereby the coil RM1 of relay R1 is energized via conductor 12, coil RM1, conductor 30a and switch S1. Energization of relay coil RM1 effects closure of all of the associated relay contact RCl-l through RC1-10, whereby a current path is established including conductor 12, field contact FC1-1, relay contact RCl-l, conductor 16a, lamp LCl, junction 18, conductor 20, junction 22 and ground terminal 24. Relay K1 remains energized by its holding circuit; opening of contact FC1-1 and switch S1 returns the system to its original condition. The illumination of lamps LR1 and LCl presents a visible indication of the specific address of the field contact FCl-l.

Assume now that field contact FC1-10 is closed and the remaining field contacts are open. Current now flows from conductor 12 through contact FC110, diode DR1-10, conductor 26a, terminal T1, conductor 28a, lamp LR1 and junction 22 to ground terminal 24. Switches SAA and S1 are operated as described above, whereby the closure of field contact FC110 is indicated by the illumination of lamp LC10. Consequently, closure of field contact PC1-10 results in illumination of lamps LR1 and LC10.

Assume now that field contact FC6-10 is closed and all the other field contacts are open. Pilot light LR-6 is now energized as a result of the current flow through conductor 12, contact FC6-10, 'diode DR6-10, conductor 26f, terminal T 6, conductor 28f, lamp -LR6 and junction 22 to ground terminal 24. Relay RM7 is energized via the flow of current through the parallel branch including conductor 42 contact 44 diode 46f, coil RM7 and conductor 45, whereby audible alarm 40 is activated. Upon closure of alarm acknowledgement switch SAA, relay K6 is energized to de-energize the audible alarm 40. Switch S6 is closed to energize relay R6 and close the relay contacts RC6-1 through the path including conductor -12, contacts FC610 and RC610, conductors 14j and 16 junction 18, conductor 20, junction 22 and ground terminal 24. By the illumination of the lamps LR6 and LC10, the operator is advised that field contact FC6-10 is the closed contact.

It is now apparent that in the illustrated embodiment, the condition of sixty remotely-located field contacts may be monitored by the use of only 16 pilot lights at a central monitor station, and that only approximately twentythree conductors between the relays and the central station are required. Consequently, as a result of the use of the multiplex relay system of the present invention, the number of components and length of the conductor means are reduced to a minimum, thus lowering the cost of the system while improving the ease of reading the indicating means to ascertain specific field contact closure.

The modification illustrated in FIG. 2 of the drawing relates to an arrangement utilizing a plurality of normally closed tfield alarm contacts. Since most of the circuity is the same as is illustrated in FIG. 1, only the components and operation which is different from FIG. 1 will be described in detail; accordingly, identical components are designated by the same reference characters, similar components are designated by a prefix X to the corresponding references characters, and added components are designated by a prefix X to new reference characters.

In FIG. 2, a plurality of normally closed field alarm contact XFC-l through XFC6-10 are connected to the common conductor 12 and are connected in series with a similar plurality of resistors XO11 through XO6-10, respectively, each of which is connected to a ground terminal X25. A plurality of PNP transistors XTRl-l through XTR6-10 are disposed between the field contacts XFC11 through XFC6-10, respectively, and the relay contacts RCl-l through RCfi-ltl, respectively. Each transistor, e.g., XTRl-l, has its emitter electrode connected to the common conductor to the parallel branches including the relay contacts RC1-1 and the diode DR1-1.

In the operation of the system of FIG. 2, it is assumed that all of the field alarm contacts XFCl-l through XFC6-10 are closed, that the switches are in their condition illustrated in FIG. 1, and that all the signal lights are deenergized. The monitoring operation of FIG. 2 is so designed that the transistors XTR, which are respectively disposed between the normally closed field contacts XFC and the multiplex relay contacts RC, are kept from firing while such field contacts are closed. For example, a positive bias from the conductor 12 and through closed field contacts XFC11 is supplied to the base electrode of the transistor XTRl-l and is paralleled to the ground terminal X through the resistor XO11 to reversely bias the transistor XTRl-l. In the event the normally closed field contacts XFC11 are opened, the transistor XTRl-l is biased into its conductive state whereby a current path is established to the common conductor leading to the parallel branches of the relay contacts RCl-l and the diodes DRl-l. The remainder of the circuit operation will then be the same as described above in connection with FIG. 1.

Various modifications may be made, of course, without deviating from the subject invention. For example, various semiconductor switching elements such as transistors, diodes, Schockley diodes and SCRs may be used in place of the field and/or relay contacts, and the appropriate lights LR1 through LR6 may be caused to blink upon initial alarm receipt, and then to be constantly illuminated upon closing of alarm acknowledgement switch SAA. This modification has the advantage of indicating to the operator that a signal exists which has not been previously acknowledged. Another modification is to connect relay RM7 with the test circuit so that upon closure of test switch ST, the audible alarm will be actuated simultaneously with the illumination of the pilot lamps.

Inasmuch as the present invention is subject to a variety of modifications and changes in details, it is intended that all matter contained in the above description as shown on the accompanying drawing, shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

l. A constant alert alarm sytem comprising a plurality of first switch means arranged in a plurality of groups, each of said first switch means being actuated when a particular condition is sensed, a plurality of second switch means each connected with one of said first switch means, respectively, to define a plurality of branches in each of said groups, each branch comprising one of said first switch means connected with one of said second switch means, first indicating means connected with said plurality of first switch means and enegrized by actuation of at least one of said first switch means for indicating that one of said groups of which said one first switch means is a part, and second indicating means connected with said plurality of second switch means for indicating that one of said branches of said one group of which said one first switch means is a part.

2. The invention as defined in claim 1 wherein said first indicating means comprises a plurality of normally de-energized first pilot lights the number of which equals the number of said groups, and wherein said second indicating means comprises a plurality of normally deenergized second pilot lights the number of which equals the number of said first switch means in the group having the largest number of first switch means, and control means for actuating all of said second switch means associated with said one group.

3. The invention as defined in claim 2 wherein said second indicating means further includes a plurality of first conductor means connecting corresponding branches of each of said groups in parallel, respectively, a plurality of second conductor means connecting said parallel corresponding branches in series with said second pilot lights, respectively, and means including a voltage source connected with said second conductor means to define a closed circuit path.

4. A constant alert alarm system comprising a plurality of normally-open field contact means arranged in a plurality of groups, each of said field contact means being closed when a particular condition is sensed, a plurality of normally-open relay contact means each connected in series with one of said field contact means, respectively, to define a plurality of series branches in each of said groups, each branch comprising one field contact means connected in series with one relay contact means, first indicating means connected with said plurality of field contact means and operable upon closure of at least one of said field contact means for indicating that one of said groups of which said one field contact means is a part, and second indicating means connected with said plurality of relay contact means for indicating that one of said series branches of said one group of which said one field contact means is a part.

5. The invention as defined in claim 4 wherein said first indicating means comprises a plurality of normally de-energized first pilot lights the number of which equals the number of said groups, and wherein said second indicating means comprises a plurality of normally de-energized second pilot lights the number of which equals the number of field contact means in the group having the largest number of field contact means, and control means for closing all of said relay contact means associated with said one group.

6. The invention as defined in claim 5 wherein said second indicating means further includes a plurality of first conductor means connecting corresponding series branches of each of said groups in parallel, respectively, a plurality of second conductor means connecting said parallel corresponding branches in series with said second pilot lights, respectively, and means including a voltage source connected with said second conductor means to define a closed circuit path.

7. The invention as defined in claim 6 wherein said first indicating means includes a plurality of equally poled unidirectionally conductive devices each having a first electrode and a second electrode, third conductor means connecting each of said series branches to one of said first electrodes of each of said devices, a plurality of fourth conductor means each connecting said second electrodes of the devices associated with each individual group with one terminal of a corresponding one of said first pilot lights, respectively, and means including a directcurrent voltage source connecting the other terminals of said first pilot lights with said series branches adjacent said field contact means 0t define a closed circuit path.

8. The invention as defined in claim 7, and further including audible alarm means operable upon closure of any of said field contact means and relay means operable to energize said audible alarm means, said relay means comprising an alarm relay coil one side of which is connected with all of said other terminals of said first pilot lights, and a plurality of fifth conductor means connecting the other side of said alarm relay coil with each of said fourth conductor means, respectively, whereby said alarm relay coil is connected in parallel across each of said first pilot lights, respectively.

9. The invention as defined in claim 8, wherein said fifth conductor means includes a plurality of normallyclosed alarm switches, respectively, and further including alarm acknowledgement means for opening those alarm switches which are conductive at a given time, respectively, whereby the audible alarm means is de-energized by operation of said alarm acknowledgement means.

'10. The invention as defined in claim 9 wherein said alarm acknowledgement means comprises a plurality of additional relays for operating said alarm switches, respectively, a plurality of sixth conductor means connecting said additional relays in parallel across said first pilot lights, respectively, a plurality of normally open acknowledgement contacts connected in series in said sixth conductor means, respectively, and means for simultaneously closing all of said acknowledgment contacts.

11. The invention as defined in claim 10, and further including a plurality of holding circuits associated with said additional relays, respectively, for holding the same in an open condition upon operation thereof by said alarm acknowledgement means.

12. A constant surveillance alarm system comprising a plurality of multiplex relays each having a plurality of normally-open relay contacts, and normally de-energized relay operating means for closing all of said relay contacts, a plurality of normally-open field contacts each connected in series with one of said relay contacts, respectively, to define a plurality of series branches each of which includes one field contact connected in series with one relay contact, normally de-energized audible alarm means connected with said plurality of multiplex relays and operable by the closure of any one of said field contacts, first pilot light means connected with said plurality of multiplex relays and operable upon closure of said one field contact means when all of said relay contacts are open for indicating that one of said relays with which said one field contact is connected, means for energizing the relay operating means of said one relay to close all of the relay contacts thereof, and second pilot light means connected with said plurality of multiplex relays and responsive to said operation of said relay operating means for indicating that one of said series branches of which the closed field contact is a part.

13. The invention as defined in claim 12, and further including test circuit means for energizing said first and second pilot light means when all of said field and relay contacts are open, and means for energizing said audible alarm means when said field and relay contacts are open.

'14. A constant alert alarm system comprising a plurality of normally-closed field contact means arranged in a plurality of groups, each of said field contact means being open when a particular condition is sensed, a plurality of normally-open relay contact means each connected with said one of said field contact means, respectively, to define a plurality of branches in each of said groups, each branch comprising one field contact means connected with one relay contact means, transistor means for each branch and being connected to said field and relay contact means, said transistor means being conductive upon opening of its corresponding field contact means, first indicating means connected with said plurality of field contact means and operable upon opening of at least one of said field contact means for indicating that one of said groups of which said one field contact means is a part, and second indicating means connected with said plurality of relay contact means for indicating that one of said branches of said one group of which said one field contact means is a part.

'15. The invention as defined in claim =14 wherein said first indicating means comprises a plurality of normally de-energized first pilot lights the number of which equals the number of said groups, and wherein said second indicating means comprises a plurality of normally deenergized second pilot lights the number of which equals the number of field contact means in the group having the largest number of field contact means, and control means for closing all of said relay contact means associated with said one group.

I16. The invention as defined in claim 15 wherein said second indicating means further includes a plurality of first conductor means connecting corresponding branches of each of said groups in parallel, respectively, a plurality of second conductor means connecting said parallel corresponding branches in series with said second pilot lights, respectively, and means including a voltage source connected with said second conductor means to define a closed circuit path.

17. The invention as defined in claim '16 wherein said first indicating means includes a plurality of like poled unidirectionally conductive means each having a first electrode and a second electrode, third conductor means connecting each of said branches to one of said first electrodes of each of said devices a plurality of fourth conductor means each connecting said second electrodes of the devices associated with each individual group with one terminal of a corresponding one of said first pilot lights, respectively, and means including a directcurrent voltage source connecting the other terminals of said first pilot lights with said branches adjacent said field contact means to define a closed circuit path.

18. The invention as defined in claim 17, and further including audible alarm means operable upon opening of any of said field contact means and relay means operable to energize said audible alarm means, said relay means comprising an alarm relay coil one side of which is connected with all of said other terminals of said first pilot lights, and a plurality of fifth conductor means connecting the other side of said alarm relay coil with each of said fourth conductor means, respectively, whereby said alarm relay coil is connected in parallel across each of said first pilot lights, respectively.

"19. The invention as defined in claim 18, and wherein said fifth conductor means includes a plurality of normally-closed alarm switches, respectively, and further including alarm acknowledgment means for opening those alarm switches which are conductive at a given time, respectively, whereby the audible alarm means is deenergized by operation of said alarm acknowledgment means.

20. The invention as defined in claim 19, wherein said alarm acknowledgment means comprises a plurality of additional relays for operating said alarm switches, respectively, a plurality of sixth conductor means connecting said additional relays in parallel across said first pilot lights, respectively, a plurality of normally open acknowledgment contacts connected in series in said sixth conductor means, respectively, and means for simultaneously closing all of said acknowledgment contacts.

21. The invention as defined in claim 20, and further including a plurality of holding circuits associated with said additional relays, respectively, for holding the same in an open condition upon operation thereof by said alarm acknowledgment means.

22. A constant surveillance alarm system comprising a plurality of multiplex relays each having a plurality of normally-open relay contacts, and normally de-energized relay operating means for closing all of said relay contacts, a plurality of normally-opened field contacts each connected with one of said relay contacts, respectively, to define a plurality of branches each of which includes one field contact connected with one relay contact, a plurality of normally non-conductive transistors, one for each branch of said field and relay contacts, means connecting each of said transistors with the field contact of its corresponding branch so that each of said transistors conducts upon opening of its corresponding field contact, normally deenergized audible alarm means connected with said plurality of multiplex relays and operable upon conducting of any one of said transistors, first pilot light means connected with said plurality of multiplex relays and operable upon opening of said one field contact means when all of said relay contacts are open for indicating that one of said relays with which said one field contact is connected, means for energizing the operating means of said one relay to close all of the relay contacts thereof, and second pilot light means connected with said plurality of multiplex relays and responsive to said operation of said relay operating means for in- 9 dicating that one of said branches of which the opened field contact is a part.

23. The invention as defined in claim 22, and further including test circuit means for energizing said first and second pilot light means when all of said cfield contacts are closed and all of said relay contacts are open, and means for energizing said audible alarm means when said field contacts are closed and said relay contacts are open.

References Cited UNITED STATES PATENTS 2,549,401 4/1951 Stein 340-413 Neill 340-413 Shillington 340-413 Doncyson 340-413 Cochinal 340-412 US. Cl. X.R. 

